Question

Two parallel wires 2 m apart carry currents of 2 A and 5 A respectively in the same direction, the force per unit length acting between these two wires is:

• A. 2 x ${10}^{-6}N{m}^{-1}$
• B. 3 x ${10}^{-6}N{m}^{-1}$
• C. 1 x ${10}^{-6}N{m}^{-1}$
• D. 4 x ${10}^{-6}N{m}^{-1}$

Answer 1

Answer: (C)

1 x ${10}^{-6}N{m}^{-1}$

Given, $I_1$ = 2 A,$I_2$ = 5 A, r = 2 m

$\therefore$ $f=\frac{{\mu }_{0}2I_1{I}_2}{4\pi r}$ = ${10}^{-7}$ x $\frac{2\times 2\times 5}{2}$ = 1 x ${10}^{-6}$N $m^{-1}$